Energy spread in ion beam analysis

In ion beam analysis (IBA) the depth profiles are extracted from the experi mentally determined energy profiles. The spectra, however, are subject to f inite energy resolution of both extrinsic and intrinsic origin. Calculation of those effects such as instrumental beam, geometry and detection-related energy and angular spreads as well as energy straggling, multiple scatteri ng and Doppler effects in the sample itself is not trivial, especially sinc e it involves treatment of nonindependent random processes. A proper accoun t for energy spread is vital in IBA not only for correct extraction of elem ental and isotopic depth profiles from the measured spectra, but already pr ior to data acquisition, in optimising experimental conditions to reach the required depth resolution at a certain depth. After a short review of the literature on the different energy spread contributions experimental exampl es are given from resonance, RES, elastic BS and ERDA practice in which an account for energy spread contributions is essential. Some further examples illustrate extraction of structural information (roughness, pore size, etc .) from elaborated depth resolution calculation for such layer structures. (C) 2000 Elsevier Science B.V. All rights reserved.